XIAO Expansion Board drawing additional 1mA

[msfujino]

The sleep current may decrease a little more. The following link may be helpful.
The expansion board has many components that cannot be turned off, so it may be difficult to reduce the current.

Sleep Current of XIAO nRF52840, Deep Sleep vs. Light Sleep

I compared the sleep current between SystemOFFSleep(DeepSleep) and SystemONSleep(LightSleep). The board service package is “Seeed nRF52 Boards 1.1.1”. To enter sleep mode, I used NRF_POWER->SYSTEMOFF = 1; for DeepSleep and RTOS delay() function for LightSleep. The pppk2 was used to measure the sleep current by applying 3.6V to the BAT pad on the backside of XIAO. The measured results were 2.4uA and 5.4A, with no significant difference. Note that the quiescent current of the 3.3V LDO is measure…